Field of the Invention
The present invention relates to a touch display panel and a driving method thereof, and in particular to a touch display panel capable of providing a normal touch function and a fingerprint identification function and a driving method of its touch mode.
Description of the Related Art
Touch-in display (TID) panel is a new type of display panel integrated with the touch function. Touch-in display panels of capacitive pattern may be classified as either mutual-capacitive type or self-capacitive type, depending on how the touch driving signals and the touch sensing signals are delivered in panels. TID of mutual-capacitive type has a path to send the touch driving signals and another path to receive the touch sensing signals. Oppositely, TID of self-capacitive type sends the touch driving signals and receives the touch sensing signals only in a path. Generally, in a conventional self-capacitive type, the common electrode is divided into a plurality of electrode blocks which are collocated as a block matrix of common electrode. Besides sending common signals in a display period, each electrode block is used as a touch sensing electrode in a touch period. The position of a touch object is determined by detecting the formation of a capacitance between the touch sensing electrode and the touch object.
The plurality of electrode blocks collocated in a matrix are connected to a driving chip via a respective metal wire of each block. The metal wire and other wiring circuits induce coupling capacitances therebetween. From the driving chip, the delivery signals get distortion and noise due to the coupling capacitances, so that the accuracy of touch sensing is decreased on the far side. In addition, the area of the electrode block is large. Such that the electrode blocks are utilized in touch sensing of normal operation, not of precise operation such as fingerprint identification.
In view of these problems, the invention provides a touch display panel and a driving method, dedicating to reduce coupling capacitances, not only in a normal touch function but also in a fingerprint identification function.